Cited by 98Hormonal and reproductive studiesExercise and Physiological ResponsesSports Performance and Training

Effects of endurance exercise on free testosterone concentration and the binding affinity of sex hormone binding globulin (SHBG)

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Fahrner, C., Hackney, A.·1998·International Journal of Sports Medicine

Abstract

Our purpose was to examine the changes in free testosterone concentration following moderately prolonged endurance exercise to determine whether such changes were due to alterations in the binding affinity of sex hormone binding globulin (SHBG). Ten trained men completed control (45 min rest) and exercise (45 min @ 70% VO2max) experimental sessions. Blood samples were collected before (pre-) and immediately after (post-) each of the sessions and analyzed for total testosterone, free testosterone, LH, FSH, cortisol, estradiol, SHBG, epinephrine and norepinephrine. The association constant (Ka) of SHBG for testosterone was assessed to evaluate binding affinity. No significant difference was seen between the pre-control and the pre-exercise session values for any of the measures. However, within the exercise session significant (p<0.01) increases in post samples were evident for total testosterone (+32.0%), free-testosterone (+39.6%), cortisol (+38.0%), norepinephrine (+365.2%) and epinephrine (+225.8%). All other hormonal changes and the responses for Ka were non-significant. The results of the correlation analysis indicated that only norepinephrine was significantly (p<0.05) related to the changes observed in free testosterone (r = +0.92). We conclude that the free testosterone increase with moderately, prolonged endurance exercise was not associated with the change in the binding affinity of SHBG. Furthermore, the data suggest that the exercise induced increase in testosterone involves increased production which may be mediated by sympathetic stimulation of the testicles.

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Research works printed but not linked: 4

  1. Dill DB, Costill DL. Calculation of percentage changes in vol- umes of blood, plasma, and red blood cells in dehydration. J Appl Physioll974; 37: 247-8.
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Authors
Fahrner, C., & Hackney, A.
Affiliations
University of North Carolina at Chapel Hill (US)
Venue
International Journal of Sports Medicine
Published
1998-01
Volume
19
Issue
01
Pages
12-15
ISSN
  • 0172-4622 (ISSN-L)
  • 1439-3964
OpenAlex
W1971707489
Cited by
98
References
16
Citations by year
2025: 3 · 2024: 2 · 2023: 5 · 2022: 3 · 2021: 4 · 2020: 3 · 2019: 4 · 2018: 5 · 2017: 3 · 2016: 4 · 2015: 2 · 2014: 6 · 2013: 4 · 2012: 5
FWCI
1.77
Type
journal article
Language
en
Open access
Locations
  • International Journal of Sports Medicine (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
  • Health Sciences › Medicine › Rehabilitation › Exercise and Physiological Responses
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
Keywords
endurance exercise, free testosterone, sex hormone-binding globulin, binding constant, total testosterone, cortisol, norepinephrine, epinephrine, sympathetic nervous system, luteinizing hormone, follicle-stimulating hormone, estradiol
MeSH terms
Adult, Analysis of Variance, Epinephrine, Humans, Hydrocortisone, Male, Norepinephrine, Physical Endurance, Protein Binding, Sex Hormone-Binding Globulin, Sympathetic Nervous System, Testis, Testosterone

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